Cylinder 1 Injector Circuit Low
The POWERSTROKE-P0261 (Power Stroke) diesel fault code means: Cylinder 1 Injector Circuit Low. This is a serious severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- advanced
- Estimated cost
- $400-$2,800 (single injector) up to $5,500 (full set of 8)
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Common Symptoms
- Cylinder 1 misfire
- Rough idle
- Loss of power
- Smoke from exhaust
- CEL
Probable Causes (Ranked by Likelihood)
- Failed cylinder 1 injector solenoid (6.0L injectors have a high failure rate) Very Likely
- Leaking oil rail o-rings (causes multiple cylinder codes) Likely
- Damaged harness under valve cover Likely
- Failed FICM driver channel Possible
Step-by-Step Diagnostic Procedure
Perform KOER injector buzz test -- non-buzzing cylinder confirms bad injector or wiring to cylinder 1.
Check for high CCT (injector contribution) variance between cylinders.
If multiple cylinders report low-side issues, suspect leaking stand-pipes or oil rail o-rings.
Replace injector #1 as a set with at least the companion cylinder (pairs share oil rail).
Common Fixes by Vehicle
What techs usually find when diagnosing POWERSTROKE-P0261 on specific platforms — tap a platform for the fix and the exact part:
2003-2007 Ford F-250/F-350 6.0L Power Stroke Advanced DIY
Injector cylinder 1 circuit low - on 6.0L this usually means the high-pressure oil rail is leaking at the STC (snap-to-connect) fitting or a stand pipe/dummy plug has cracked. Perform an air test on the high-pressure oil system; if it won't hold 30 psi, pull the valve covers and inspect stand pipes.
Labor: 4.0-6.0 hrsFrequently Asked Questions
What is P0261 on a 6.0L Power Stroke?
P0261 on a 6.0L Power Stroke (2003-2007) indicates: Cylinder 1 Injector Circuit Low. This is a known diagnostic trouble code on this engine family and typically points to the causes listed above.
Can I drive with P0261 on my Power Stroke?
Only drive short distances to get to a repair facility. Continued operation may cause further damage.
How much does it cost to fix P0261?
Repair cost is typically $400-$2,800 (single injector) up to $5,500 (full set of 8) depending on the underlying cause and whether you DIY or use a shop. Diagnostic time alone runs $100-$180 at most independent diesel shops.
P0261 on Other Platforms
The same code ID appears across other engines, vehicles, and equipment. Diagnostic flow varies by platform — see the matching breakdown: